Fluid flow control providing increased energy extraction

ABSTRACT

Systems and methods configured to control ambient fluid flow for increased energy extraction using a turbine are disclosed. In various examples, a system can include a convergent nozzle configured to receive and accelerate an ambient flow of fluid and a turbine including one or more rotor blades. The convergent nozzle can include a configuration having a ratio of a nozzle inlet area to a nozzle outlet area between about 1.5:1 to about 10:1, inclusive. An interior nozzle surface can include one or more contours aligned with a direction of the ambient flow of fluid. The convergent nozzle can include apertures in a region near a nozzle outlet. The apertures can be selectively controlled to draw additional fluid flow into the accelerated flow to avoid excessive stress on turbine components. The rotor blades can have a length equal to or slightly greater than a radius of the nozzle outlet.

CLAIM OF PRIORITY

This non-provisional patent application claims the benefit of priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/387,330, entitled “SYSTEMS AND METHODS TO CONTROL FLUID FLOW FOR ENERGY EXTRACTION,” (Attorney Docket No. 3293.001PRV), filed on Sep. 28, 2010, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

This patent document pertains generally to the control of fluid flow. More particularly, but not by way of limitation, this patent document pertains to systems and methods configured to control fluid flow for increased energy extraction.

BACKGROUND

Energy extraction systems and methods utilizing liquid or gaseous fluid flow are known. For example, wind turbines convert kinetic energy of wind flow into mechanical work for applications such as power generation. Similarly, hydro turbines extract energy from flowing water for generating power or driving machinery. These turbines are typically dependent on the ambient fluid flow velocity at a turbine interface, and more particularly, at rotor blades of the turbines.

The quantity of energy available for capture in existing turbines is generally proportional to a cross-sectional area where the ambient fluid flow and rotor blades interact. Noteworthy, however, is that the cost of turbines increases and material requirements become more rigorous as rotor blade size increases.

Existing turbines deliver electric power to a grid system at times when ambient flow conditions are favorable to generating electricity, independent of whether there is user demand for the electricity. The turbines require a minimum ambient fluid flow velocity to operate and have a maximum tolerable fluid flow velocity, beyond which turbine components experience stresses posing a significant risk of failure. As a preventative measure, existing turbines are often shutdown when ambient fluid flow velocity is high and poses a risk of failure.

OVERVIEW

The present inventor has recognized that the relationship between fluid flow velocity and kinetic energy available for extraction is cubic, thereby elevating the desirability of fluid flow velocities greater than typical ambient flow velocities, the risk of component failure notwithstanding. The present inventor has further recognized, among other things, that energy extraction improvements can be realized by providing and using one or more of: (i) a convergent nozzle configured to receive and accelerate an ambient flow of fluid to a higher velocity prior to rotor blade reception, (ii) selectively controllable apertures near a nozzle outlet serving to lower or otherwise modulate, if needed, the velocity of an accelerated fluid flow at the rotor blades, (iii) a duct external to or within the convergent nozzle to create zones with differing fluid (e.g., airflow) velocities at the nozzle outlet, or (iv) rotor blades having a size, shape, or contour that is configured to extract greater usable energy at higher fluid flow velocities. Further yet, the present inventor has recognized that storage of turbine-captured energy until there is user demand enhances the value of turbine systems.

A system can include a convergent nozzle configured to receive and accelerate an ambient flow of fluid and a turbine including one or more rotor blades. The convergent nozzle can include a configuration having a ratio of a nozzle inlet area to a nozzle outlet area between about 1.5:1 to about 10:1, inclusive. An interior nozzle surface can include one or more contours aligned with a direction of the ambient flow of fluid. The convergent nozzle can include apertures in a region near a nozzle outlet. The apertures can be selectively controlled to draw additional fluid flow into the accelerated flow to avoid excessive stress on the turbine components. The rotor blades can have a length equal to or slightly greater than a radius of the nozzle outlet. Optionally, additional control over fluid flow can be provided using a cylindrical or convergent duct positioned within the convergent nozzle or an external annular airfoil ring positioned near the nozzle inlet or the nozzle outlet.

Control, extraction, and storage of the energy captured by the system can be achieved using hydraulic pumps, motors, or accumulators to defer electric power generation until user demand calls for it. A solar energy receiver can be used to capture additional energy and transmit the energy in the form of heat to a heat exchanger incorporated within the accumulator. The accumulator can compound the stored energy from the turbine system, using heat from the solar energy receiver to increase stored power, and optionally, waste heat from an exothermic process prior to being converted to electricity.

To better illustrate the systems and methods disclosed herein, a non-limiting list of examples is provided here:

In Example 1, a system comprises a convergent nozzle configured to receive and accelerate an ambient flow of fluid and a turbine including a rotor, with the rotor configured to convert kinetic energy of the accelerated flow of fluid into mechanical energy suitable to drive an energy extraction device.

In Example 2, the system of Example 1 is optionally configured such that the energy extraction device includes an electric generator or a hydraulic pump.

In Example 3, the system of any one or any combination of Examples 1 or 2 is optionally configured such that the convergent nozzle includes a configuration having a ratio of a nozzle inlet area to a nozzle outlet area between about 1.5:1 to about 10:1, inclusive.

In Example 4, the system of any one or any combination of Examples 1-3 optionally further comprises a platform configured to align the convergent nozzle and the rotor with a direction of the ambient flow of fluid.

In Example 5, the system of Example 4 is optionally configured such that an interior surface of the convergent nozzle includes a contour configured to be aligned with the direction of the ambient flow of fluid, the contour being defined using a reference line extending a length of the convergent nozzle, from a focal point of a nozzle inlet to a focal point of a nozzle outlet, with a reference point being about one half the distance along the reference line, a circumference of the interior surface of the convergent nozzle at each point, L_(Rx), along the reference line being defined by,

Circumference=2π(R _(O)+(C/2)+C*[(L _(Rx) *|L _(Rx)|)]/L ² _(IO)) and

Intended Factor of Acceleration=((2C/R_(O))+(C²/R² _(O)))+1, where L_(Rx) is a positive amount if, from the reference point, the point at which the circumference is being determined is the distance along the reference line starting at the reference point in a direction toward the nozzle inlet, and L_(Rx) is negative where it is the distance along the reference line from the reference point in a direction toward the nozzle outlet, R_(I) is the radius of the convergent nozzle at the nozzle inlet, R_(O) is the radius of the convergent nozzle at the nozzle outlet, C is the difference R_(I)-R_(O), and L_(IO) is the length of the convergent nozzle determined along the reference line.

In Example 6, the system of any one or any combination of Examples 1-5 optionally further comprises or more ducts positioned within the convergent nozzle, with the ducts configured to create zones with a differing fluid velocity at a nozzle outlet.

In Example 7, the system of any one or any combination of Examples 1-6 is optionally configured such that the convergent nozzle includes a material selected from the group consisting of: aramid, liquid crystal polymer, ultra-high strength polyethylene, and carbon fiber.

In Example 8, the system of any one or any combination of Examples 1-7 is optionally configured such that the rotor includes one or more blades having a length about equal to or slightly larger than a radius of a nozzle outlet.

In Example 9, the system of Example 8 is optionally configured such that at least one of the one or more blades includes a blade tip turned at an angle to a longitudinal extension of the corresponding blade, the angle oriented in a direction toward an airfoil surface experiencing lift.

In Example 10, the system of Example 8 is optionally configured such that at least one of the one or more blades includes a blade having a plate positioned perpendicular to a longitudinal extension of the corresponding blade at the tip and at such other places along the span of the blade where it is desirable to inhibit fluid flow in the span-wise direction.

In Example 11, the system of any one or any combination of Examples 8-10 is optionally configured such that at least one of the one or more blades includes a wedge-like shape on a leading edge of an airfoil to reduce vortices at a blade tip.

In Example 12, the system of any one or any combination of Examples 8-11 is optionally configured such that an asymmetric camber of the one or more blades becomes more symmetric with respect to each blade's chord with the increasing distance away from a rotor hub until it is substantially symmetric near a blade tip, and wherein a length of the chord gradually increases with distance away from the hub.

In Example 13, the system of Example 12 is optionally configured such that the camber, the length of the chord, and an angle with respect to a plane of rotation of each blade is variable, in a continuous or a discontinuous manner, to correspond to a fluid velocity at the nozzle outlet created by one or more ducts positioned with an interior surface of the convergent nozzle or an external annular ring, having airfoil characteristics, positioned about a circumference of a nozzle inlet or the nozzle outlet.

In Example 14, the system of any one or any combination of Examples 12 or 13 is optionally configured such that the rotor hub includes an annular disc centered on a shaft driving the energy extraction device, and the one or more blades are adjustably coupled to the hub in such a way as to allow for modification of an attack angle of each blade's airfoil.

In Example 15, the system of any one or any combination of Examples 8-14 is optionally configured such that the one or more blades are directly or indirectly coupled to a shaft driving the energy extraction device using a rope of inelastic material, with the rope configured to redirect rotational forces on the one or more blades.

In Example 16, the system of any one or any combination of Examples 8-15 optionally further comprises an external annular ring, having airfoil characteristics, positioned about a circumference of the nozzle inlet or the nozzle outlet.

In Example 17, the system of Example 16 is optionally configured such that the airfoil includes a greater circumference on a leading inlet edge than on a trailing outlet edge and is positioned measured perpendicularly from the nozzle outlet at a distance approximately equal to its camber.

In Example 18, the system of any one or any combination of Examples 1-17 is optionally configured such that the convergent nozzle includes one or more apertures in a region near a nozzle outlet.

In Example 19, the system of Example 18 is optionally configured such that the one or more apertures are selectively controllable and, as the accelerated flow of fluid reaches or exceeds a preselected velocity, the apertures are opened to draw additional fluid flow into the accelerated fluid flow and modulate such accelerated flow to avoid excessive stress on the rotor.

In Example 20, a method comprises accelerating an ambient flow of fluid, including funneling the ambient flow of fluid into and through a convergent nozzle to a rotor of a turbine and driving an energy extraction device, which includes one or both of an electric generator or a hydraulic pump.

In Example 21, the method of Example 20 optionally further comprises transmitting power captured by driving the hydraulic pump to a hydraulic accumulator or a hydraulic motor attached to the electric generator.

In Example 22, the method of Example 21 optionally further comprises capturing heat energy from the sun or waste heat from an exothermic process and transmitting the heat energy to the hydraulic accumulator using a heat transfer fluid and a heat exchanger.

In Example 23, the method of Example 22 optionally further comprises transmitting energy from the hydraulic accumulator to a central system including one or more hydraulic motors attached to one or more electric generators.

In Example 24, the method of any one or any combination of Examples 20-23 is optionally configured such that funneling the ambient flow of fluid into and through the convergent nozzle includes accelerating the ambient flow of fluid at a ratio between about 2.5:1 to about 7:1, inclusive.

In Example 25, the method of any one or any combination of Examples 20-24 optionally further comprises positioning the convergent nozzle on a platform, including rigidly securing the convergent nozzle to the platform and mounting the platform to a tower such that the convergent nozzle and platform orientate a nozzle inlet with a direction of the ambient flow of fluid.

In Example 26, the method of any one or any combination of Examples 20-25 is optionally configured such that accelerating the ambient flow of fluid includes accelerating an ambient flow of wind or an ambient flow of water.

In Example 27, the method of any one or any combination of Examples 20-26 optionally further comprises coupling one or more rotor blades to a hub centered on a drive shaft of the energy extraction device, including enabling rigging affixed to the hub and between individual rotor blades to transmit angular forces on the blades to the hub.

In Example 28, the method of Example 27 is optionally configured such that coupling the one or more rotor blades to the hub includes coupling the rotor blades to the hub in a range from (a) each blade being perpendicular to the hub at the point of connection to (b) each blade being displaced up to 0.10 radians from a tangential point at which the blade extends perpendicularly.

In Example 29, the method of any one or any combination of Examples 20-28 optionally further comprises coupling one or more rotor blades to a hub mounted on a releasable roller clutch, with the roller clutch, when engaged, powering a drive shaft coupled to the energy extraction device.

In Example 30, the system or method of any one or any combination of Examples 1-29 is optionally configured such that all elements or options recited are available to use or select from.

These and other examples, advantages, and features of the present systems and methods will be set forth in part in the following Detailed Description. This Overview is intended to provide non-limiting examples of the present subject matter; it is not intended to provide an exclusive or exhaustive explanation. The Detailed Description is included to provide further information about the present systems and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals can be used to describe similar components throughout the several views. Like numerals having different letter suffixes can be used to represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

FIG. 1 illustrates a side view of a system for receiving and controlling ambient fluid flow, including a convergent nozzle and a turbine including a generator and one or more rotor blades positioned atop a tower, as constructed in accordance with at least one embodiment.

FIG. 2A illustrates a profile view of a convergent nozzle including a plurality of controllable apertures near a nozzle outlet, with the apertures configured for manipulating an accelerated ambient fluid flow, as constructed in accordance with at least one embodiment.

FIG. 2B illustrates an open and closed view of a controllable aperture for placement near a nozzle outlet, with the aperture configured for manipulating an accelerated ambient fluid flow, as constructed in accordance with at least one embodiment.

FIG. 3A illustrates a straight contour of an interior surface of a convergent nozzle, as constructed in accordance with at least one embodiment.

FIG. 3B illustrates a concave contour of an interior surface of a convergent nozzle, as constructed in accordance with at least one embodiment.

FIG. 3C illustrates an S-shaped contour of an interior surface of a convergent nozzle, as constructed in accordance with at least one embodiment.

FIG. 4 illustrates a front view of a convergent nozzle and a 5-blade rotor configuration centered in a nozzle outlet, as constructed in accordance with at least one embodiment.

FIG. 5A illustrates a rotor blade, as constructed in accordance with at least one embodiment.

FIGS. 5B-5D illustrate cross-sectional airfoil views of the rotor blade of FIG. 5A at spaced locations along the blade's length, as constructed in accordance with at least one embodiment.

FIGS. 6A-6C illustrate profile views of various rotor blades including a leading edge modified to alter sound produced by the rotor blade during operation or reduce drag at a blade tip, as constructed in accordance with some embodiments.

FIG. 7 illustrates a side view of a system for controlling ambient fluid flow including a support frame, a platform center beam, and a turbine including a generator and one or more rotor blades positioned atop a tower, as constructed in accordance with at least one embodiment.

FIG. 8 illustrates a top view of a support frame and a platform center beam configured to support a convergent nozzle and turbine components, as constructed in accordance with at least one embodiment.

FIGS. 9A-9B illustrate a configuration of a controllable aperture for placement near a nozzle outlet, the apertures configured for manipulating an accelerated ambient fluid flow, as constructed in accordance with at least one embodiment.

FIG. 10 illustrates a servo-mechanical device, as constructed in accordance with at least one embodiment.

FIG. 11 illustrates a side view of a system including one or more rotor blades positioned atop a tower, the rotor blades driving a hydraulic pump and energy being transmitted to a hydraulic accumulator or a hydraulic motor attached to an electric generator, as constructed in accordance with at least one embodiment.

FIG. 12 illustrates a top sectional view of a convergent nozzle including one or more ducts positioned within the nozzle and an external annular ring, having airfoil characteristics, positioned near a nozzle outlet for varying a fluid velocity at one or more rotor blades, as constructed in accordance with at least one embodiment.

FIG. 13 illustrates a front view of a convergent nozzle including one or more ducts positioned within the nozzle and an external annular ring, having airfoil characteristics, positioned near a nozzle outlet for varying a fluid velocity at one or more rotor blades, as constructed in accordance with at least one embodiment.

FIGS. 14A-14B illustrate front and side views of a rotor blade including a plurality of segments, with the segments corresponding to differing fluid velocity zones at a nozzle outlet resulting from one or more ducts positioned within a convergent nozzle and an external annular ring, as constructed in accordance with at least one embodiment.

FIG. 15 illustrates a side view of a system including a hydraulic energy transmission and storage subsystem supplemented with a solar energy capture subsystem, as constructed in accordance with at least one embodiment.

FIG. 16 illustrates a top view of a convergent nozzle and annular rings positioned about a circumference of a nozzle inlet and a nozzle outlet to further aid in control of ambient fluid flow, as constructed in accordance with at least one embodiment.

DETAILED DESCRIPTION

The present subject matter provides systems and methods for extracting energy from flowing fluids by accelerating or otherwise controlling such fluid flow to a higher or more ideal velocity prior to being received at a turbine interface, and more particularly, at one or more rotor blades of the turbine. By establishing control over the fluid flow prior to extracting kinetic energy, the systems and methods can optimize fluid flow velocity at the point of extraction and moderate fluctuations in the ambient dynamics of the fluid, particularly those of relative direction and velocity.

In various examples, the system can include a wind turbine (e.g., a horizontal-axis wind turbine) and a convergent nozzle configured to orientate and accept on-coming ambient wind flow. In other examples, the system can include a water or hydro turbine and a convergent nozzle configured to orientate and accept on-coming ambient water flow. A decreasing circumference of the convergent nozzle causes the speed of the wind or water flow to increase until it is received by the wind or water turbine. In some examples, a modified form of the convergent nozzle can be used with a modified form of a conventional turbine. These modifications can include one or more of: (i) a reduction of the turbine dimensions relative to the expected power output to decrease a rotor blade swept area, (ii) changes in the placement of the rotor and the addition of rigging to extend means of redirecting the linear fluid flow force into rotational energy, (iii) modification of rotor blade shapes, as enabled by the rigging and reduced relative dimensions, (iv) the use of nozzle outlet apertures to introduce additional mass into the accelerated fluid flow to reduce the flow's velocity while maintaining the mass flow rate, as well as mitigate drag sources associated with the expected component velocities, and (v) the use of ducts external to or within the nozzle to create zones of differing fluid velocities at the nozzle outlet.

FIG. 1 illustrates a side view of a system 100 for controlling ambient fluid flow. The system 100 can include a turbine 102, a convergent nozzle 104, and a tower 106. The convergent nozzle 104 can include a nozzle inlet 108, a nozzle outlet 110, and an interior contoured surface 112. The nozzle outlet 110 can be configured to direct an accelerated flow of fluid onto one or more rotor blades 114 connected to an energy extraction device, such as an electric generator 116. In some examples, the nozzle outlet 110 can be configured to direct the accelerated flow of fluid onto rotor blades connected to an energy extraction device in the form of a hydraulic pump.

A platform or carriage 118 can be used to support and facilitate orientation of the convergent nozzle 104. In some examples, the platform 118 can be connected atop the tower 106 using a pivot connection joint. The pivot connection joint can allow the platform 118 to align the convergent nozzle 104 and the one or more rotor blades 114 with a direction of the ambient fluid flow.

FIG. 2A illustrates a profile view of a convergent nozzle 204 including a plurality of controllable apertures 220 configured for manipulating an accelerated ambient fluid flow within the nozzle 204. The plurality of controllable apertures 220 can be located near a nozzle outlet 210 and can function like a Venturi mechanism by opening up in size as the exhaust flow velocity approaches a turbine design limit, thereby decreasing exit velocity of the flow. As illustrated in the example of FIG. 2B, the controllable apertures 220 can be configured as iris style valves 222. The iris style valves 222 can be opened as desired and govern the flow of fluid through the valves to control nozzle outlet 210 velocity.

A ratio of the area of a nozzle inlet 208 to that of the nozzle outlet 210 can establish the degree of fluid flow acceleration. In an example, the convergent nozzle 204 includes a configuration having a ratio of the nozzle inlet 208 area to the nozzle outlet 210 area between about 1.5:1 to about 10:1, inclusive. In an example, the ratio of the nozzle inlet 208 area to the nozzle outlet 210 area is between 2.5:1 to 7:1. The convergent nozzle can include a material selected from the group consisting of: aramid, liquid crystal polymer, ultra-high strength polyethylene, and carbon fiber, for example.

FIGS. 3A-3C illustrate optional contours 350, 352, 354 for an interior contoured surface 112 (FIG. 1) of a convergent nozzle 104 (FIG. 1), 204 (FIG. 2A).

Each of the contours 350, 352, 354 can be symmetrical about a nozzle axis so as to form a circular cross-section and can be oriented in a direction of an ambient flow of fluid. In particular, FIG. 3A illustrates a straight contour 350. FIG. 3B illustrates a concave contour 352 that is believed to offer minimum drag for turbine sites with low ambient fluid flow velocities. FIG. 3C illustrates an S-shaped contour 354 that is believed to offer a high degree of fluid flow control, particularly for turbine sites having favorable ambient fluid flow velocities.

The contours 350, 352, 354 of the interior contoured surface 112 of the convergent nozzle 104, 204 can be defined using a reference line extending a length of the nozzle, from an axial focal point of a nozzle inlet to an axial focal point of a nozzle outlet, with a reference point being about one half the distance along the reference line. The contours 350, 352, 354 can be truncated at a location before the reference point, at the reference point, or after the reference point. A circumference of the interior contoured surface 112 of the convergent nozzle 104, 204 at each point along the reference line, the circumference at L_(p) can be defined by:

Circumference=2π(R _(O)+(C/2)+C*[(L _(Rx) *|L _(Rx)|)]/L ² _(IO))  (Equation 1)

and

Intended Factor of Acceleration=((2C/R _(O))+(C ² /R ² _(O)))+1  (Equation 2),

where L_(Rx) is a positive amount if, from the reference point, the point at which the circumference is being determined is the distance along the reference line starting at the reference point in a direction toward the nozzle inlet, and L_(p) is negative where it is the distance along the reference line from the reference point in a direction toward the nozzle outlet, R_(I) is the radius of the convergent nozzle at the nozzle inlet, R_(O) is the radius of the convergent nozzle at the nozzle outlet, C is the difference R_(I)-R_(O), and L_(IO) is the length of the convergent nozzle determined along the reference line.

FIG. 4 illustrates a front view of a convergent nozzle 404 and a 5-blade 414 rotor configuration centered in a nozzle outlet 410. In the example shown, a length 460 of the rotor blades 414 is less than or approximately equal to the radius of the nozzle outlet 410. In some examples, the length of the rotor blades 414 is slightly larger than the radius of the nozzle outlet 410.

Because of the dynamics of fluid flow at the nozzle outlet 410, developed by the convergent nozzle 404, the rotor blade 414 configuration can be tailored to expected fluid flows, including fluid velocities, apparent angles, and expected turbulence around each blade's airfoil. A rotor hub 450 can include an annular disc centered on a shaft driving an energy extraction device (e.g., an electric generator or a hydraulic pump). The rotor blades 414 can be adjustably coupled to the hub 450 in such a way as to allow for modification of an attack angle of each blade's airfoil. In an example, the coupling between the rotor blades 414 and the hub 450 can include a rope of inelastic material, which can be configured to redirect rotational forces of the blades 414. In an example, the coupling between the rotor blades 414 and the hub 450 ranges from (a) each blade being perpendicular to the hub at the point of connection to (b) each blade being displaced up to 0.10 radians from a tangential point at which the blade extends perpendicularly. The hub 450 can be mounted on a releasable roller clutch that, when engaged, powers the drive shaft of the energy extraction device.

FIGS. 5A-5D illustrate various views of an example rotor blade 514. Specifically, FIG. 5A illustrates a profile view of the rotor blade 514, and FIGS. 5B-5D illustrate cross-sectional, airfoil views of the rotor blade 514 at spaced apart locations along the blade's length 560. The cross-sectional, airfoil views of the rotor blade 514 offer optional cambers and chord lengths 530 at points along the blade 514, demonstrating a trend that is believed to be beneficial for greater operation fluid flow velocities, in some examples. In each of FIGS. 5B-5D, the thickness of the airfoil is at its maximum about 3/10 of the distance along the chord length 530 from front-to-back and the maximum camber is at about ½ of this distance. An asymmetric camber of the rotor blade 514 can become more symmetric with respect to the blade's chord with distance away from a rotor hub until it is substantially symmetric near a blade tip 552.

A leading edge of an airfoil can include a wedge-like shape to reduce vortices at or near the blade tip 552. The camber, the length of the chord, and an angle with respect to a plane of rotation of the rotor blade 514 can be adjustable, in a continuous or a discontinuous manner, to correspond to a fluid flow velocity at a convergent nozzle outlet. The angle of attack (e.g., the angle between the chord length 530 and the apparent wind direction as the rotor blade 514 is rotating through the fluid flow during operation) can be based on the ratio of a nozzle inlet to a nozzle outlet of a convergent nozzle.

FIGS. 6A-6C illustrate profile views of example rotor blades 614. These rotor blade 614 alternatives provide different ways of addressing issues of drag as each blade's airfoil moves at a relatively high velocity through a flowing fluid. The elbowed blade 660 of FIG. 6A is expected to produce less sound than conventional rotor blades. The scimitar blade 662 of FIG. 6B is believed to be a widely adaptable design. The blade 664 of FIG. 6C is expected to provide greater drag reduction in high operating velocity implementations than conventional rotor blades. The blade 664 of FIG. 6C can include a blade tip 652 turned at an angle to a longitudinal extension of the blade. In an example, a rotor blade 614 can include a blade tip having a plate positioned substantially perpendicular to a longitudinal extension of the blade.

FIG. 7 illustrates a side view of a system 700 for controlling ambient fluid flow including a support frame 790, a convergent nozzle 704, and a turbine 702 including a generator 716 and one or more rotor blades 714 positioned atop a tower 706. A turbine beam 770 can be vertically attached to a platform 718 on a first end and support the generator 716 and rotor blades 714 of the turbine 702 on a second end. The rotor blades 714 can be mounted to clear the turbine beam 770 and platform 718 when the system 700 is in operation. The platform 718 can include a central beam serving as the principal support for the system 700.

The convergent nozzle 704 can be mounted using a frame 790 consisting of side supports 772 attached to the platform central beam 718 near each of its ends by cross beams 774, 776. The cross beams 774, 776 can function to keep the convergent nozzle 704 in line with the beam 718 and all other mounted components. In some examples, the front cross beam 774 is substantially vertical to the ground and the rear cross beam 776 is slanted at about a 30° angle from vertical. The platform central beam 718 can rest on and attach to a pivot 796, and the cross beams 774, 776 can be attached to the beam 718 fore and aft of the pivot 796 so as to effectively deliver the torque for yaw control to the full system 700. Mounted at each end of the side supports 772 can be a frame arch to which the ends of the convergent nozzle 704 can be attached. In some examples, a first frame arch 792 is positioned at the nozzle inlet and a second frame arch 794 is positioned at the nozzle outlet. A system of braces can extend from the side supports 772 to the top of the arches 792, 794 at the front and back of the convergent nozzle 704.

FIG. 8 illustrates a top view of the support frame 790 and the platform central beam 718 mounted atop the pivot 796. The two side supports 772 can be attached to the platform central beam 718 at the front by cross beam 774 and at the back by cross beam 776. The front cross beam 774 can be longer than the rear cross beam 776 in approximately the same proportions as the diameter of the nozzle inlet to the nozzle outlet. The front vertical arch 792 and the rear vertical arch 794 can be mounted at each end of the side supports 772.

FIGS. 9A-9B illustrate a configuration of a controllable aperture for placement near a nozzle outlet, with the aperture configured for manipulating an accelerated ambient fluid flow within a convergent nozzle. The controllable aperture 920 can function like a Venturi mechanism by opening up in size as an exhaust fluid flow velocity approaches a turbine design limit, thereby decreasing exit velocity of the fluid flow. The controllable aperture 920 in this illustrated example includes two adjacent covers 940, 942. These covers 940, 942 can be attached to a convergent nozzle at a pivoting point 944 and can be opened and closed by a servo-mechanical device, such as the device shown in FIG. 10. In operational examples, counterclockwise rotation can serve to open the controllable aperture 920 by spooling off a wire 946 attached to the cover at the side opposite the pivot, and spooling in wire 946 attached to the cover on the same side as the pivot but offset, such that this retraction of the wire 946 can cause the cover to rotate. The servo-mechanical device can be actuated by a sensor upstream of the controllable aperture 920.

FIG. 10 illustrates a servo-mechanical device 1000, as constructed in accordance with at least one embodiment. In this example, the servo-mechanical device 1000 consists of two spools: a larger spool 1080 for a connection to a cover end opposite a pivot and a smaller spool 1082 for a wire attached to the cover adjacent to the device 1000. The two spools can be sized such that a ratio of the circumference of the larger spool 1080 to the smaller spool 1082 is the same or approximately the same as the distance between the points at which the respective wires 1084 are attached to the covers 940, 942 (FIGS. 9A-9B) and the pivot points 944 (FIGS. 9A-9B).

FIG. 11 illustrates a side view of a system 1100 for controlling ambient fluid flow and capturing energy. The system 1100 can include a turbine 1102 including one or more rotor blades 1114, a convergent nozzle 1104, a tower 1106, and a hydraulic system 1130. Integration of the hydraulic system 1130 can allow an electric generator to be conveniently located at or near an Earth surface, and can further allow for the capture of kinetic fluid energy for later use in power generation (e.g., when there's little to no ambient wind). The convergent nozzle 1104 can be configured to direct an accelerated flow of fluid onto the one or more rotor blades 1114. The rotor blades 1114 can be connected to an energy extraction device in the form of a hydraulic pump 1116. The hydraulic pump 1116 can capture energy from the fluid flow and transmit the energy to a hydraulic motor 1132 or to a hydraulic accumulator 1136 through high-pressure pipelines 1138. In some examples, the rotor blades 1114 can be connected to a plurality of hydraulic pumps 1116, which are in turn connected to the hydraulic motor 1132 or to the hydraulic accumulator 1136. The hydraulic motor 1132 can be attached to one or more electric generators 1134 for power generation. The hydraulic accumulator 1136 can temporarily store the captured energy for later transmission to the hydraulic motor 1132 and associated electric generators 1134.

FIG. 12 illustrates a top sectional view of a convergent nozzle 1204 including one or more ducts 1260 positioned within an interior surface 1262 of the nozzle and an external annular ring 1264, having airfoil characteristics, positioned near a nozzle outlet 1210. The one or more internal ducts 1260 and the external annular ring 1264 can alter a fluid velocity that is output from the convergent nozzle 1204 and received by one or more rotor blades 1214. More specifically, the internal ducts 1260 and the external annular ring 1264 can alter fluid flow velocity through the creation of differing velocity zones at spaced distances from a central axis 1266.

In this example, the one or more ducts 1260 positioned within the interior surface 1262 of the convergent nozzle 1204 can include an inner duct 1268 at least partially nested within an outer duct 1270. The ducts 1268, 1270 can be located in an approach to and/or at a throat of the convergent nozzle 1204, thereby enabling the alternation of fluid flow velocities directed at sections of the rotor blades 1214. The inner duct 1268 can include a cylindrical shape having parallel slides. The parallel sides can be retracted 1268A when an ambient fluid flow is of a desirable velocity, or can be partially 1268B or fully extended 1268C when the ambient fluid flow is slower than desired. The extension of the parallel sides can increase a degree of flow acceleration in the nozzle outlet zones further from the central axis 1266. The inner duct 1268 can, for example, include a radius of between about 0.15 and about 0.30 times the radius of the inlet of the convergent nozzle 1204 and can be extended or telescoped toward the inlet 1208. Optionally, one of more additional ducts with, for example, a radius between about 0.25 and about 0.40 of the next inner-most duct can be included. The additional ducts can be capable of expansion such that an inlet 1208 area is greater than an outlet 1210 area and thus, capable of modifying the fluid flow velocity at the outlet to an extent different from other zones at the convergent nozzle outlet 1210. The one or more ducts 1260 can change in shape either by extension toward a convergent nozzle 1204 inlet plane or by increasing or decreasing a circumference of the duct inlet or both.

The internal outer duct 1270 can include a convergent configuration having an inlet-to-outlet ratio similar to that of the primary convergent nozzle 1204. The diameter of outer duct 1270 can be increased to alter the relative increase in fluid flow velocities of the outer two zones—increasing that of the inner zone and decreasing that of the outer zone in the expanded position. The outer duct 1270 can be moved along the axis 1266, thereby modifying an area of the two annular zones—a first at the inlet of the duct 1270 and a second at the outlet of the duct 1270.

The external annular ring 1264 can enclose the one or more rotor blades 1214, thereby guiding air across the blade tips 1252, minimizing vortex formation, and providing for greater consistency of fluid flow on the rotor blades 1214. The external annular ring 1264 can include a greater circumference on a leading inlet edge 1272 than a trailing outlet edge 1274. The external annular ring 1264 can be positioned from the convergent nozzle outlet 1210 at a distance approximately equal to its camber. The external annular ring 1264 can be positioned in the region of the nozzle outlet 1210 such that the components at least partially overlap. An area of the overlap formed by the leading inlet edge 1272 of the external annular ring 1264 and the nozzle outlet 1210, on a plane that is perpendicular to the direction of fluid flow, can be greater than an area formed by the non-overlapping portions of the external annular ring 1264. The external annular ring 1264 can extend beyond the plane of rotation of the system's rotors 1214, with the sides of the external annular ring 1264 being perpendicular to the plane at that point and thereafter becoming divergent.

In some examples, an external annular ring is additionally or alternatively positioned near a nozzle inlet 1208 (see, e.g., FIG. 16). A leading edge of the external annular ring can be positioned one-half of its chord length forward of the leading edge of the inlet 1208, and the chord line of the ring can be oriented at an angle from about 8° to about 20° with respect to the central axis 1266 of the nozzle 1204. The distance between the external annular ring and the outer edge of the inlet 1208 can be approximately the camber of its airfoil.

FIG. 13 illustrates a front view of the convergent nozzle 1204, the one or more ducts 1268, 1270 positioned within the convergent nozzle 1204, and the external annular ring 1264 positioned near the nozzle outlet of FIG. 12. The convergent nozzle 1204 can include a nozzle inlet 1208 and a nozzle outlet 1210. The inner duct 1268 can include a similarly-sized inlet and outlet. The outer duct 1270 can include an inlet 1269 size greater than an outlet 1271 size. The external annular ring 1264 can include a greater circumference on a leading inlet edge 1272 than a trailing outlet edge 1274.

FIGS. 14A-14B illustrate example front and side views of a rotor blade 1414 that has modified to present distinct airfoils corresponding to the fluid velocity zones created by the internal ducts 1268, 1270 and the external annular ring 1264 of FIG. 12. Each zone segment of the rotor blade 1414 can include a chord line angle relative to a rotor blade plane of rotation 1467 that changes in either a continuous or a discontinuous fashion along the length of the blade. The changing chord line angles can accommodate an expected apparent direction of fluid flow from a related outlet zone. Points along the length of the rotor blade 1414 where there is a discontinuous change in the chord line angle between two zone segments can include a fence, perpendicular to the rotor blade plane of rotation 1467, for separating any difference in air pressure on the rotor blade's 1414 surfaces of the two sections.

In the example of FIGS. 14A-14B, a first segment 1401 corresponding to velocity zone 1201 (FIG. 12) can include a largest angle of orientation 1402 relative to the rotor blade plane of rotation 1467 to accommodate a lower fluid velocity. A second segment 1403 corresponding to velocity zone 1203 (FIG. 12) can include a smaller angle of orientation 1404 relative to the plane of rotation 1467 and a wider size to optimize lift. A third segment 1405 corresponding to velocity zone 1205 (FIG. 12) can include an even smaller angle of orientation 1406 relative to the plane of rotation 1467 and an even wider size to accommodate both fluid velocity and relatively high rotational speeds at the outer rotor blade region. An outer most fourth segment 1407 corresponding to velocity zone 1207 (FIG. 12) can be oriented away from a direction of the fluid flow to minimize tip drag.

FIG. 15 illustrates a side view of a system 1500 configured to capture solar energy. The solar system 1500 can be added to a sunward side of a turbine tower 106 (FIG. 1) to capture solar energy and transmit the heat energy to a hydraulic accumulator 1536. The solar system 1500 can include a solar energy receiver 1501; an array of heliostatic or solar tracking mirrors 1502A, 1502B, 1502C, 1502D; the hydraulic accumulator 1536; high pressure pipelines 1538, 1539; a heat exchanger 1505; a hydraulic motor 1532; and one or more electric generators 1534. The heliostatic or solar tracking mirrors 1502A, 1502B, 1502C, 1502D can include a large number of mirrors to track the sun and reflect sufficient energy to appropriately support pressurization of the hydraulic accumulator 1536. The high pressure pipelines 1538 can convey heated energy transfer fluid to the heat exchanger 1505 positioned inside the hydraulic accumulator 1536, which can contain a pressurized gas 1506 (e.g., N₂ or CO₂), increasing the force on stored hydraulic fluid 1507 and providing sufficient energy to drive the hydraulic motor 1532 and the one or more electric generators 1534. The energy transfer fluid can be returned to the solar energy receiver 1501 by the pipeline 1539 after the heat has been removed.

Similar to the capture of heat energy from the sun and transmission to the hydraulic accumulator, a system can be configured to capture waste heat from an exothermic process and transmit the heat energy to the hydraulic accumulator 1536 using a heat transfer fluid and a heat exchanger.

FIG. 16 illustrates a top view of a convergent nozzle 1604 and annular rings 1663, 1664 positioned about a circumference of a nozzle inlet 1608 and a nozzle outlet 1610. The annular rings 1663, 1664 can aid in control of an ambient fluid flow. The annular ring 1663 positioned about the nozzle inlet 1608 can include an airfoil profile 1601 having an outer lift surface in the area of the convergent nozzle inlet 1608 configured to create an area of increased pressure. The annular ring 1664 positioned about the nozzle outlet 1610 can include an airfoil profile 1602 configured to shroud one or more turbine rotor blades. The airfoil profile 1602 can induce a fluid flow of an accelerated nature in the region of the blade tips to reduce blade tip drag.

Closing Notes:

The velocity or strength of ambient wind or water flow at a location can vary, and an average velocity or strength value of the ambient fluid flow can provide an indication of the amount of energy a typical wind or hydro turbine can produce there. The present systems and methods can advantageously enhance ambient fluid flows, while also modulating velocities at a turbine-defined upper end of a fluid velocity range. This fluid flow enhancement and control can, among other things, increase turbine productivity and reliability, as well as provide for lower start-up speeds and reduced operating costs relative to conventional turbines.

The present systems and methods can employ various components on a coordinated basis to establish the enhanced degree of control over the ambient flow of fluid prior to such fluid's interaction with a wind or hydro turbine. In various examples, the present systems and methods can be adapted or retrofitted to function with one or more components of existing turbines. Through use of the present systems and methods, existing turbines can be made more compact by, among other things, reducing rotor blade length without compromising on energy extraction capabilities.

The above Detailed Description includes references to the accompanying drawings, which form a part of the Detailed Description. The drawings show, by way of illustration, specific embodiments in which the present systems and methods can be practiced. These embodiments are also referred to herein as “examples.”

The above Detailed Description is intended to be illustrative and not restrictive. For example, the above-described examples (or one or more elements thereof) can be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. Also, various features or elements can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

In this document, the terms “a” or “an” are used to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “about” and “approximately” are used to refer to an amount that is nearly, almost, or in the vicinity of being equal to a stated amount.

In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended; that is, a system, kit, or method that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” “third,” and so forth are used merely as labels, and are not intended to impose numerical requirements on their objects.

The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 

1. A system, comprising: a convergent nozzle configured to receive and accelerate an ambient flow of fluid; and a turbine including a rotor, the rotor configured to convert kinetic energy of the accelerated flow of fluid into mechanical energy suitable to drive an energy extraction device.
 2. The system of claim 1, wherein the energy extraction device includes an electric generator or a hydraulic pump.
 3. The system of claim 1, wherein the convergent nozzle includes a configuration having a ratio of a nozzle inlet area to a nozzle outlet area between about 1.5:1 to about 10:1, inclusive.
 4. The system of claim 1, further comprising a platform configured to align the convergent nozzle and the rotor with a direction of the ambient flow of fluid.
 5. The system of claim 4, wherein an interior surface of the convergent nozzle includes a contour configured to be aligned with the direction of the ambient flow of fluid, the contour being defined using a reference line extending a length of the convergent nozzle, from a focal point of a nozzle inlet to a focal point of a nozzle outlet, with a reference point being about one half the distance along the reference line, a circumference of the interior surface of the convergent nozzle at each point, L_(Rx), along the reference line defined by, Circumference=2π(R _(O)+(C/2)+C*[(L _(Rx) *|L _(Rx)|)]/L ² _(IO)) and Intended Factor of Acceleration=((2C/R_(O))+(C²/R² _(O)))+1, where L_(Rx) is a positive amount if, from the reference point, the point at which the circumference is being determined is the distance along the reference line starting at the reference point in a direction toward the nozzle inlet, and L_(Rx) is negative where it is the distance along the reference line from the reference point in a direction toward the nozzle outlet, R_(I) is the radius of the convergent nozzle at the nozzle inlet, R_(O) is the radius of the convergent nozzle at the nozzle outlet, C is the difference R_(I)-R_(O), and L_(IO) is the length of the convergent nozzle determined along the reference line.
 6. The system of claim 1, further comprising one or more ducts positioned within the convergent nozzle, the ducts configured to create one or more zones with a differing fluid velocity at a nozzle outlet relative to an adjacent zone.
 7. The system of claim 1, wherein the convergent nozzle includes a material selected from the group consisting of: aramid, liquid crystal polymer, ultra-high strength polyethylene, and carbon fiber.
 8. The system of claim 1, wherein the rotor includes one or more rotor blades having a length about equal to or slightly larger than a radius of a nozzle outlet.
 9. The system of claim 8, wherein at least one of the one or more rotor blades includes a blade tip turned at an angle to a longitudinal extension of the corresponding rotor blade, the angle oriented in a direction toward an airfoil surface experiencing lift.
 10. The system of claim 8, wherein at least one of the one or more rotor blades includes a blade tip having a plate positioned perpendicular to a longitudinal extension of the corresponding rotor blade.
 11. The system of claim 8, wherein at least one of the one or more rotor blades includes a wedge-like shape on a leading edge of an airfoil to reduce vortices at a blade tip.
 12. The system of claim 8, wherein an asymmetric camber of the one or more rotor blades becomes more symmetric with respect to each blade's chord and distance away from a rotor hub until it is substantially symmetric near a blade tip, and wherein a length of the chord gradually increases with distance away from the rotor hub.
 13. The system of claim 12, wherein the camber, the length of the chord, and an angle with respect to a plane of rotation of each rotor blade is adjustable, in a continuous or a discontinuous manner, to correspond to a fluid velocity at the nozzle outlet created by one or more ducts positioned within the convergent nozzle or an external annular ring, having airfoil characteristics, positioned about a circumference of a nozzle inlet or the nozzle outlet.
 14. The system of claim 12, wherein the rotor hub includes an annular disc centered on a shaft driving the energy extraction device, the one or more rotor blades being adjustably coupled to the rotor hub in such a way to allow for modification of an attack angle of each rotor blade's airfoil.
 15. The system of claim 8, wherein the one or more rotor blades are directly or indirectly coupled to a shaft driving the energy extraction device using a rope of inelastic material, the rope configured to redirect rotational forces on the one or more rotor blades.
 16. The system of claim 8, further comprising an external annular ring, having airfoil characteristics, positioned about a circumference of a nozzle inlet or the nozzle outlet.
 17. The system of claim 16, wherein the airfoil includes a greater circumference on a leading inlet edge than on a trailing outlet edge and is positioned from the nozzle outlet at a distance approximately equal to its camber.
 18. The system of claim 1, wherein the convergent nozzle includes one or more apertures in a region near a nozzle outlet.
 19. The system of claim 18, wherein the one or more apertures are selectively controllable such that, as the accelerated flow of fluid reaches or exceeds a preselected velocity, the apertures are opened to draw additional fluid flow into the accelerated fluid flow and modulate such accelerated flow to avoid excessive stress on the rotor.
 20. A method, comprising: accelerating an ambient flow of fluid, including funneling the ambient flow of fluid into and through a convergent nozzle to a rotor of a turbine; and driving an energy extraction device, including one or both of an electric generator or a hydraulic pump.
 21. The method of claim 20, further comprising transmitting power captured by driving the hydraulic pump to a hydraulic accumulator or a hydraulic motor attached to the electric generator.
 22. The method of claim 21, further comprising capturing heat energy from the sun or waste heat from an exothermic process and transmitting the heat energy to the hydraulic accumulator using a heat transfer fluid and a heat exchanger.
 23. The method of claim 22, further comprising transmitting energy from the hydraulic accumulator to a central system including one or more hydraulic motors attached to one or more electric generators.
 24. The method of claim 20, wherein funneling the ambient flow of fluid into and through the convergent nozzle includes accelerating the ambient flow of fluid at a ratio between about 2.5:1 to about 7:1, inclusive.
 25. The method of claim 20, further comprising positioning the convergent nozzle on a platform, including rigidly securing the convergent nozzle to the platform and mounting the platform to a tower such that the convergent nozzle and platform orientate a nozzle inlet with a direction of the ambient flow of fluid.
 26. The method of claim 20, wherein accelerating the ambient flow of fluid includes accelerating an ambient flow of wind or an ambient flow of water.
 27. The method of claim 20, further comprising coupling one or more rotor blades to a rotor hub centered on a drive shaft of the energy extraction device, including enabling rigging affixed to the rotor hub and between individual rotor blades to transmit angular forces on the rotor blades to the rotor hub.
 28. The method of claim 27, wherein coupling the one or more rotor blades to the rotor hub includes coupling the rotor blades to the rotor hub in a range from (a) each blade being perpendicular to the hub at the point of connection to (b) each blade being displaced up to 0.10 radians from a tangential point at which the blade extends perpendicularly.
 29. The method of claim 20, further comprising coupling one or more rotor blades to a rotor hub mounted on a releasable roller clutch, the roller clutch, when engaged, powering a drive shaft coupled to the energy extraction device. 